EXPERIMENTAL STUDY OF THE DIFFUSION COMBUSTION OF A HIGH-SPEED ROUND HYDROGEN MICROJET PART 2. LIFTED FLAME, SUPERSONIC FLOW

Read more Scenario of supersonic diffusion combustion of a round hydrogen microjet is presented in this work. The main features of supersonic diffusion combustion of a hydrogen round microjet are shown: disappearance of a «bottleneck flame» region, lifted flame from the nozzle exit and existence of supersonic «shock cells» in the lifted turbulent flame. The main reason for this scenario of diffusion combustion connected with a temperature factor is found i.e. with existence of thin-walled micronozzles with a small thermal capacity and a possibility of their quenching that doesn't give the chance to exist of the «bottleneck flame» region at big speeds of a microjet efflux. It is shown that with growth of temperature of a micronozzle heating from the «bottleneck flame» region at the same speed of a microjet efflux growth of its spatial size (l/d) is found.

Keywords:
hydrogen round microjet, diffusion combustion, «bottleneck flame» region, thinwalled micronozzle, micronozzle heating. 
УДК 544.452.42

EXPERIMENTAL STUDY OF THE DIFFUSION COMBUSTION OF A HIGH-SPEED ROUND HYDROGEN MICROJET PART 2. LIFTED FLAME, SUPERSONIC FLOW